1. Field of the Invention
This invention refers to railway switching machines, and, in particular, to those devices which are used to move the rail end points of switch point assemblies. More specifically, this invention refers to a device for use either with switch point assemblies having connected rail end points, or with movable point frog assemblies.
2. Background Art
As is commonly known, railway switch point assemblies include two rail end points which are tapered rail profiles capable of deflecting to move between two different positions, in order to facilitate the correct alignment of the track components for the desired path of rolling stock transiting through the switch point assembly. The switch point assembly has two deflectable or movable rail end points which move in concert with one another between first and second alternative positions. In a first alternative position, a first one of these movable rail end points can be aligned with a first fixed stock rail to facilitate passage of the rolling stock straight through the switch point onto a first set of fixed rails. In a second alternative position, the second movable rail end point can be aligned with a second fixed stock rail to facilitate passage of the rolling stock onto a second set of fixed rails, such as to divert the rolling stock onto a siding. The remote ends of the two deflectable rails almost intersect, near the location where the second set of fixed rails diverges from the first set of fixed rails.
At the ends of the deflectable rails where they almost intersect, it is necessary to provide a means for the rims of the wheels of the rolling stock to cross the fixed rail which is not being followed, and to pass from one of the deflectable rails onto the desired set of fixed rails. Frog assemblies are used for this purpose, wherein the left rail of one set of rails beyond the frog assembly, and the right rail of the other set of rails beyond the frog assembly form a “V-point” adjacent to the point where the deflectable rails cross. At this point, the remote ends of the deflectable switch point rails can form “wing rails” on either side of the V-point.
Some of these frog assemblies can have a fixed V-point, a fixed wing rail, and a deflectable wing rail which can deflect as the wheel rims pass through, allowing the rolling stock to follow the desired set of fixed rails. These are “fixed point” frog assemblies. Still other frog assemblies can have fixed wing rails and a moving or deflectable V-point which can be aligned with either of the wing rails, according to the desired path of the rolling stock. These are commonly called “movable point” frog assemblies.
In the typical switch point assembly, the two deflectable rail end points are moved by rods protruding from the opposite extremities of a unit often called the switch point machine. Inside the switch point machine, the rods are usually connected to a device with a reciprocating straight line motion, which is powered by a motor unit which is generally placed to the side of the rails. The state of the art includes numerous switch point machines for railway split point movements. For example, EP 1,245,469 to Biagiotti describes such a switch point machine. Such mechanisms are normally installed at the switch point, and they are typically applied only to move the split rail end points of the switch point assembly.
Therefore, it is desirable to provide a simple type of mechanism which can be used either to move the deflectable rail end points of the switch point assembly or to move the deflectable V-point of a movable point frog assembly.